Portable derrick.



J. D. READ. PORTABLE DERRICK. APPLICATION FILED MAY 14, 1913.

Patented June 16, 1914.

2 SHEETSSHEET 1.

fizz/(7Z2. 196441 J. D. READ. PORTABLE DERRICK. 7 APPLICATION FILED MAY 14, 1913.

Patented June 16, 1914.

2 SHEETS-SHEET 2.

JENNIE D. READ, OF DAVIS, CALIFORNIA.

PORTABLE DERRICK.

incense.

To all whom it may concern Specification of Letters Patent.

Application filed May 14, 1913.

Be it known that I, JENNIE D. READ, a

citizen of the United States, residing at Davis, in the county of Yolo and State of California, have invented certain new and useful Improvements in Port-able Derricks,

. as stated formed in two parts bolted toof which the following is a specification.

My invention relates to improvements in.

portable derricks, and has for its leading object to provide a rigid, compact, and durable derrick, which can be compactly crated in knock-down form for shipment and can be easily set up and made ready for use, and

when thus set up can be easily moved from place to place as required.

A further object of the invention is to provide a derrick in which the boom can be lowered to enable the height of the derrick to be reduced to permit of passing under telephone wires and the like.

A further object of the invention is to provide a derrick in which the friction of the tilting boom in its bearing will be re duced to a minimum; which derrick will possess merit in point of inexpensiveness, durability, and compactness; and which will prove highly satisfactory and efficient in use.

To attain the desired objects, the invention consists in the provision of a derrick embodying certain novel features of construction and combinations of parts, substantially as disclosed herein.

Figure 1 is a side elevation of a derrick constructed in accordance with and embodying the principles of my invention, the tilting boom being shown in full lines in its normal position and in dotted lines in its position when it has been lowered to permit passage of the derrick under telephone wires or the like. Fig. 2 is a horizontal sectional view on the line 22 of Fig. 1, and Fig. 3 is a vertical sectional view on the line 33 of Fig. 2.

Referring by numeral to the drawings, in which similar numerals of reference denote corresponding parts in the several views thereof: the numeral 1 designates the base or foundation timbers, in which are jour- Patented June 16, 1914:.

Serial No. 767,550.

base. The mast is further braced with the vertical truss rods '11, which are threaded onto the annular plates 12 and 13 through which the mast passes at its upper and lower ends, respectively, thus advantageously bracing the mast. The yoke or casting 6 is gether by the bolts 1%, and has an annular ball race 15 therein in which travel the ball bearings 16, which thus provide a practically frictionless bearing for the vertically shdable sleeve or collar 17 embracing the mast and adjustable vertically thereon by means of the link 18 and lever 19 with rack 20. From this construction, it will be seen that the mast is spaced from the yoke or casting 6 by the sleeve 17, which may be adjusted vertically on said mast by means of the lever 19 and connecting link 18, while the ball bearings 16 in the annular ball race of the yoke provide a practically frictionless bearing for said sleeve. It will also be noted that by forming the yoke or casting 6 in two parts, said casting may be easily taken apart and adjustments and repairs made, while the device as a whole may be easily and quickly assembled or reduced to knock-down form. Fitting in a recess 21 in said sleeve 17 is the curved bearing plate 22 of the inclined bracing arm 23 of the vertically adjustable boom 24:, which is connected to the mast at its upper extremity by the angular supporting brace 25 and is braced and connected to the inclined bracing arm 23 by the pair of inclined connecting arms 26, this construction pr oviding means for holding the boom in raised position. The boom may be lowered as indicated in dotted lines in Fig. 1 to permit the passage of the derrick under telephone wires and the like by simply exerting a downward pull on the sliding collar or sleeve 17 through lever 19 and connecting link 18. The boom is pr0- vided at each end with the usual pulleys 27, over which passes the hoisting rope 28, one end of which is to be connected to the article to be elevated and the other end to be pulled upon either manually or by a team of horses or the like.

In operation, the derrick is drawn to the place desired, and the mast and boom swing into proper position to elevate the desired article. In the event that it is desired to lower the boom, which as seen in Fig. 1 extends to a height greater than that of the mast, it is simply necessary to operate the lever, which through its connection with the vertically sliding sleeve will cause said boom to lower to the position shown in Fig. 1, thus permitting the passage of the derrick beneath structures under which it would ordinarily be impossible to pass.

From the foregoing description, taken in connection with the accompanying drawings, the construction and operation of my improved derrick will be readily seen and appreciated, and it will be apparent to all that I have provided a derrick which will efficiently and reliably perform the objects heretofore stated.

1. In a portable derrick, in combination, a base, a rotary mast thereon, a movably mounted boom for said mast, a casting embracing said mast and formed with a ball race, said casting being fixedly supported at a distance above said base balls in said race, a sleeve embracing the mast and slidable thereon with said balls as bearings, said, sleeve supporting a part of said boom, and a lever and connections to adjust said sleeve.

2. In a portable derrick, the combination of a base, a mast step, a rotary mast mounted therein, a casting embracing said mast and formed with socket members, inclined truss rods seated in said sockets and connected to the base, vertical truss rods connecting said casting with the base, a sleeve embracing said mast for a part of its length and having a frictionless bearing on said casting, a boom-bearing in said sleeve, a boom mounted for vertical movement and means to adjust said sleeve vertically, said boom being supported on said boom bearing.

8. In a portable derrick, the combination of a base, wheels therefor, a mast step, a rotary mast mounted therein, a two-part casting for said mast, inclined braces Connecting said casting and base, vertical brace rods connecting said casting and step, a sleeve embracing said mast and having an anti-friction bearing 011 said casting, a boom seated in a recess in said sleeve, a link connected to said sleeve, a lever connected to said link for adjusting said sleeve vertically 011 said mast to raise and lower said boom, and a rack for said lever.

In testimony whereof I afiix my signature in presence of two witnesses.

JENNIE D. READ.

Witnesses:

ALICE CURsoN, ANNABEL Tnoor.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

